Not applicable.
Highway snow and ice control frequently is carried out by governmental authorities with the use of dump trucks, which are seasonally modified by the addition of snow-ice treatment components. These components will include forwardly-mounted plows and rearwardly-mounted mechanisms for broadcasting materials such as salt or salt-aggregate mixtures. The classic configuration for the latter broadcasting mechanism includes a feed auger extending along the back edge of the dump bed of a truck. This hydraulically driven auger effects a metered movement of material from the bed of the truck into a rotating spreader disc or xe2x80x9cspinnerxe2x80x9d which functions to broadcast the salt across the pavement being treated. To maneuver the salt-based material into the auger, the dump bed of the truck is progressively elevated as the truck moves along the highway or pavement to be treated.
Operating systems employed for these snow and ice control implements have been substantially improved over the past decade. An initial such improvement has been achieved through the utilization of microprocessor driven controls over the hydraulics employed with the seasonally modified dump trucks. See Kime, et al., U.S. Pat. No. Re 33,835, entitled xe2x80x9cHydraulic Systems Used with Snow-Ice Removal Vehicle, reissued Mar. 3, 1992. This Kime, et al. patent describes a microprocessor-driven hydraulic system for such trucks with a provision for digital hydraulic valving control which is responsive to the instantaneous speed of the truck. With the hydraulic system, improved controls over the extent of deposition of snow-ice materials is achieved.
This form of control has been employed to control the rate of salt deposition such that the granular material may be ejected from a delivery vehicle at a rate commensurate with the trucks forward speed. Such an arrangement conserves snow-ice materials and permits deposition at desirably higher truck speeds. See in this regard, Kime, et al, U.S. Pat. No. 5,318,226 entitled xe2x80x9cDeposition of Snow-Ice Treatment Material from a Vehicle with Controlled Scatterxe2x80x9d, issued Jun. 7, 1994. This approach is sometimes referred to as a xe2x80x9czero-velocityxe2x80x9d method for salt distribution.
Investigations into the chemical-physical phenomena of pavement borne ice formation have recognized the importance of salt in the form of a salt brine in breaking the bond of ice with underlying pavement. It is this brine, as opposed to mere granular salt, which reacts to attack ice formations. This phenomenon has lead to the development of improved techniques for generating brine of sufficient concentration to break the ice-pavement bond. For example, Kime in U.S. Pat. No. 5,988,535 entitled xe2x80x9cMethod and Apparatus for Depositing Snow-Ice Treatment Material on Pavementxe2x80x9d; issued Nov. 23, 1999 describes the deposition of a granular salt-brine material on pavement as a continuous narrow band. The result of such deposition is a highly effective snowice treatment procedure with an efficient utilization of salt materials. An improvement in this technique is described in application for U.S. patent application Ser. No. 09/512,199 entitled xe2x80x9cMethod and Apparatus for Depositing Snow-Ice Treatment Material on Pavementxe2x80x9d by Kime, filed Feb. 24, 2000 in which narrow band ejection of salt and brine is provided in a manner wherein it is encountered by the rear drive wheels of a dump truck. For both approaches of the above-described narrow band deposition, the dump truck structuring is such that use may be made of them for purposes other than snow-ice control during winter seasons. In this regard, highway maintenance organizations require that the dump trucks be capable of being used for such purposes as hauling gravel and/or pothole repair materials.
While substantial improvements have been recognized as with these brine formation snow-ice control systems, the majority of highway maintenance organizations continue to employ conventional highway maintenance dump trucks which are retrofitted each season with plows, a cross-bed auger which typically is bolted to the truck bed beneath the bed tailgate and a hydraulically driven spinner. Control over the rate of material feed generally is by the truck operator. When these trucks are utilized for winter maintenance purposes, the plows are uncoupled; the augers are covered with a plate arrangement and the spinner may be removed or pivoted out of the way. With the emergence of the above-rioted ice-pavement bond studies, the ubiquitous snow-ice control retrofit approaches now are called upon to additionally mount relatively large brine tanks which permit a substantially increased utilization of brine in combination with granular salt. The brine preferred, in terms of cost, is a sodium chloride solution. However, the amount of this form of brine called for in snow-ice treatment is quite substantial compared to alternate brines, such as calcium chloride based solutions which typically are orders of magnitude greater in cost but lower in amounts or volumetric requirements. Typically, the only practical location for the brine tanks is at the rear of these trucks, regions between the axles exhibiting little or no space for tank mounting. These polymeric tanks, in addition to being bulksome, when filled with brine solution are quite heavy and difficult to maneuver on and off trucks.
The Ohio Department of Transportation (ODOT) developed a combination tailgate assembly for winter season use. This assembly mounts the brine tanks at the rear of a tailgate and couples both the spinner and auger at the bottom of the tailgate. The combinational assembly then is mounted on a truck utilizing a conventional front-end loader. The maximum available brine tank capacity for the assemblies is about 70 gallons. An undesirable aspect of these devices resides in a rearward diversion of the center of gravity of the tailgate to the extent that, when the dump bed is raised, the tailgate will open only a few inches when the brine tanks are empty and not at all should they be filled. However, these combinational tailgate assemblies represent a substantial improvement in terms of convenience of mounting over the conventional bed-mounted auger-spinner approach.
On occasion, the dump trucks will be loaded with both salt and brine and sent out on patrol prior to the commencement of inclement weather. Where such weather fails to materialize, then these trucks will return to base at which point in time it is necessary that the salt load be dumped. Because the tailgates cannot be opened, it then becomes necessary to again use the front-end loader approach to remove the combinational tailgates entirely in order to carry out necessary salt dumping. The same problem is encountered where the trucks, for example, are dispatched to carry out plowing alone without salt treatment. To achieve necessary traction, the trucks are loaded with salt notwithstanding the fact that such salt is not dispersed. Accordingly, as the trucks return, again it is necessary to dump the salt, which cannot be carried out without removal of these non-pivoting combinational tailgates.
The present invention is addressed to a vehicle and associated tailgate assembly, the latter being configured for snow-ice control procedures. Employing a tailgate frame supporting brine supply tanks which extend through that frame and pivotally mounting the frame rearwardly of a normal pivot position, the tailgate functions in a manner wherein its center of gravity resides at a vertical plane passing through the rearwardly disposed pivot connection. Thus, the tailgate assembly may pivot open when the vehicle dump bed to which it is attached is raised, having been unlatched by the operator. This opening occurs even though the tailgate carrying brine tanks may be full of brine fluid.
Liquid brine fluid weight distribution achieving the desired tailgate center of gravity is developed through the use of a tank cross section resembling an inverted, truncated right triangle. Thus configured and oriented, the tank assembly extends inwardly through the tailgate frame. With this arrangement, substantial enhancement of the volumetric capacity also is realized while desired opening pivoting performance of the tailgate is achieved. In this regard, for a preferred embodiment, tank capacity is elevated from about 70 gallons to about 140 gallons and this enhancement is evolved with a desired truck rear end tank mounting.
Carried by the tailgate frame beneath the brine tank assembly is a cross transport mechanism implemented as an auger carrying a sequence of flights which are driven from first to last to maneuver particulate material essentially across the widthwise extent of the vehicle dump bed into an outlet . From this outlet the material passes to a broadcasting assembly implemented as a hydraulically driven spinner. The feed opening of this auger is an elongate one generally presented to the widthwise extent of the dump bed of the vehicle. Ingress of the salt material into the auger for distribution to the outlet is made possible and facilitated by the noted sloping forward wall of the brine tank assemblage. That sloping wall serves to overcome any tendency of the granular salt materials to xe2x80x9cbridgexe2x80x9d or coalesce and fail to move towards the auger-based transport mechanism.
Because it is desirable to admix a substantial amount of brine fluid with particulate salt materials, fluid brine from the brine tank assemblage is introduced to that granular salt at a location adjacent the noted last flight of the auger assembly. Thus, the last flight is utilized as a mixing device for developing a brine-salt slurry ultimately to be deposited or broadcast from the spinner assembly.
Simple mounting of the tailgate assembly to the rims of the dump bed walls at the rearward portion of the dump bed is carried out utilizing two links, one positioned at each side of the tailgate and having rearward apertures formed therein pivotally coupled with the upper region of the tailgate frame. Each link additionally contains a medial aperture and a forward aperture. In this regard, medial aperture is connected with the xe2x80x9cnormalxe2x80x9d tailgate pivoting mechanism attached to the dump bed rims. The forward aperture is coupled with an installed stabilizing bracket through the utilization of pin connections for the latter two apertures. Mounting of the tailgate assembly to the dump bed readily is carried out utilizing, for example, a front end loader.
Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.
The invention, accordingly, comprises the apparatus possessing the construction, combination of elements and arrangement of parts which exemplify the following detailed description.
For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings.